Why are fabrics tested for color fastness to rubbing? When people wear clothes, the fabric and the material will produce friction; Various splicing parts will also produce friction; In depending on the object, there will also be friction; These frictions are likely to result in color transfer due to the poor color fastness of the friction fabric. Thus affecting the appearance of clothing image. Therefore, it is reasonable for the test of color fastness to friction to be listed as a basic technical requirement in GB 18401 "National Basic Safety Technical Specification for Textiles".

Because the color fastness of friction is so important, as a professional textile fabric development practitioners, we should have a deeper understanding of the factors affecting the color fastness of friction.

Common standard for testing colour fastness to rubbing

Chinese standard: GB/T 3920

International standard: ISO 105 X12/X16

American standard: AATCC 8/AATCC 116

JIS L0849 Type I /Type II

The color fastness to friction of textiles is divided into dry color fastness and wet color fastness.

Color fastness to friction refers to the degree of fading of dyed fabric after friction, which is to test the resistance of dye to mechanical friction.

Factors affecting colour fastness to rubbing:

a. Fabrics with poor color fastness to dry friction: rough surface or ground fleece, fuzziness fabrics, hard fabrics such as linen, denim fabrics, paint printed fabrics, dry friction makes dye or other colored substances accumulated on the surface wear off, or part of the colored fibers break to form colored particles, which reduces the color fastness to dry friction; In addition, there is a certain Angle between the pile on the surface and the contact surface of the ground cloth, which is not parallel, so that the friction resistance of the ground cloth increases, and the color fastness to dry grinding decreases.

b. Cellulose fabrics are usually dyed with reactive dyes. There are two reasons for the transfer of dyes from the test fabric to the ground cloth:

▲ Water-soluble dyes are transferred to the ground cloth when wet friction, the active dyes and cellulose fibers are combined by covalent bonds, this type of bond is very strong, not because of friction and fracture, mainly through the van der Waals force and cellulose fibers combined with dyes (is the common said floating color), in the wet state friction will be transferred to the ground cloth, Resulting in poor color fastness to wet friction.

▲ Dyed fibers break in the process of friction, forming tiny colored fiber particles and transferred to the cloth, resulting in poor color fastness to wet friction.

c. The color fastness to wet friction of dyed fabric with reactive dyes is closely related to the depth of dyeing. When dyeing dark color, the dye concentration is higher, because excessive dye can not be combined with the fiber, but can only accumulate on the surface of the fiber into floating color, which seriously affects the color fastness to wet wear of the fabric. The pre-treatment degree of cellulose fiber fabric directly affects the color fastness to wet abrasion. Pre-treatment such as mercerization, burning, boiling and bleaching can make the surface of the fabric smooth, reduce friction resistance and improve the color fastness to wet friction.

d. For light and thin polyester fabric, when dry friction is carried out, because the fabric is loose, under the action of friction, the local slip of the fabric will increase the friction resistance; However, when this kind of fabric is tested for color fastness to wet friction, water plays the role of lubrication during wet grinding because of polyester's low water absorption. Therefore, the color fastness of fabric to wet grinding is better than that to dry grinding in this case. Dark colors such as black, red, or navy blue have a more pronounced effect. But for corduroid fabrics, under wet conditions, due to the dye and printing process, the usual color fastness to wet friction is only about 2, not better than dry friction color fastness.

e. The softener added in the finishing process plays a lubricating role, which can reduce the friction coefficient and reduce the dye shedding. Cationic softener and anionic reactive dye will react to form lake, which will reduce the dye solubility and improve the color fastness to wet friction of the fabric. The softener of hydrophilic group is not conducive to the improvement of color fastness of wet friction.